1. Field of the Invention
The present invention relates to a fishing line length measuring device for fishing reels and particularly to a fishing line length measuring device for determination of the amount unwound or the amount wound of the fishing line based on the number of spool revolutions.
2. Description of the Art
Recent fishing reels are often capable of determining the unwound or wound length of the fishing line, which enables the exact setting of fishing devices at the shelf where there are plenty of fish and a display of the distance to the fishing device point when casting the bait.
The inventor of the present invention has already proposed a fishing line measuring device for fishing reels capable of highly precise measurement of the unwound or wound length of the fishing line regardless of the line diameter in the Japanese Patent Application Laid-open No. 276011/1989.
The above fishing line measuring device uses a determined constant corresponding to the spool shape together with the total number of spool revolutions when the fishing line is wound to the specified wound line diameter level and the actual number of spool revolutions during unwinding or winding of the fishing line to obtain the fishing line length with the formula (1) below.
FIG. 19 shows a specific example explaining the relation between the number of revolutions made by the spool 1 where the spool 1 is of straight type with invariable winding width m', the outer diameter of the fishing line 3 wound onto the spool 1 and the line length. Symbols in the figure have the meanings as follows:
d.sub.1 : Wound line diameter of the fishing line 3 at the specified wound line diameter level 5; PA1 d.sub.0 : Bottom diameter of the spool 1; PA1 d.sub.m : Outer diameter of the wound line changed by unwinding or winding of the fishing line 3; and PA1 h: Groove depth of the spool 1 up to the specified wound line diameter level 5 PA1 na is the actual number of revolutions made by the spool 1 in letting out or winding up of the fishing line 3, PA1 a is the constant for h and PA1 b is the constant for d.sub.1.
The conventional embodiment above uses as the basic data the total number of revolutions n of the spool 1 when the fishing line 3 is wound up to the specified wound line diameter level 5 and the actual number of spool 1 revolutions na when the wound line diameter changes from d.sub.1 to d.sub.m by revolutions of the spool 1 to perform the following formula stored in the ROM of the microcomputer: EQU L'=(a/n)(na).sup.2 +b(na) (1)
where n is the total number of the spool 1 revolutions when the fishing line 3 is wound up to the specified wound line diameter level 5,
Thus, the let out line length L' corresponding to the actual number of revolutions na made by the spool 1 is determined.
The total number of revolutions n and the actual number of revolutions na at the spool 1 are respectively counted by an up-down counter and the counted values are stored in the RAM of the microcomputer.
For the conventional line length measuring device above, however, it is inconvenient to determine the constant for the unwound line amount when actually fishing. Specifically, the wound line diameter d1, which is substantially the same as the maximum winding diameter of the spool 1, is used as the specified wound line diameter level 5, and the total number of revolutions n made by the spool 1 up to the specified wound diameter level 5 is input to the RAM as the total line length of the fishing line 3. Since the specified wound line diameter level 5 is used as the base of the let out line diameter, the user must wind up the fishing line 3 up to the specified wound line diameter level 5 once to input the total number of revolutions n made by the spool 1 as the basic data. It was bothersome to wind up the fishing line 3.
Besides, when the wound line diameter of the fishing line 3 wound onto the spool 1 is below the specified wound line diameter level 5 set near the maximum wound line diameter of the spool 1, the basic data cannot be input which disables operation of the formula (1); if the fishing line 3 has a length resulting in a wound line diameter exceeding the specified wound line diameter level 5, then the basic data cannot be input for the amount exceeding the specified wound diameter level 5.
Thus, the above line length measuring device has drawbacks that the fishing line 3 must be wound up to the specified wound diameter level 5 once and that the line length cannot be determined when the wound line diameter of the fishing line 3 is more or less than the specified wound diameter level 5. To have the line length measuring device work, the user has to add unnecessary fishing line just to make the line reach the specified wound line diameter level 5 or cut the excessive part over the specified wound line diameter level 5.
Besides, to precisely check whether the fishing line 3 is wound up to the specified wound diameter level 5, an input scale for specified line winding detector according to the Utility Model Laid-open No. 9566/1992 disclosed by the inventor of the present invention is separately needed. Thus, checking is bothersome and the operability is not good.
In addition, though fishermen tend to use a base line with a diameter different from the fishing line 3 in actual fishing, the conventional line length measuring device as above uses the number of revolutions n made by the spool 5 up to the specified wound diameter level 5 as the basic data for line length measurement, and it is impossible to input the basic data when the base line is used.